RESEARCHES REGARDING THE INFLUENCE OF DAYS OPEN AND DAYS DRY ON THE MILK PRODUCTION IN FIRST CALVING ROMANIAN SPOTTED COWS

L.T. CZISZTER, S. ACATINCĂI, G. STANCIU, SIMONA BAUL, I. TRIPON, SILVIA ERINA, D. GĂVOJDIAN, EUGENIA KOVACS

Abstract


The purpose of the paper was to study the influence of the length of days open anddays dry on the milk yield, as well as to establish correction coefficients tostandardize the lactations of the Romanian Spotted primiparous cows according tothese factors. Researches were carried out on 667 lactations from Romanian Spottedprimiparous cows. Lactations were assigned to one of the eight classes of days open:20-40, 41-60, 61-80, 81-100, 101-120, 121-140, 141-160, and over 160 days. For daysdry seven classes were formed: 0-20, 21-40, 41-60, 61-80, 81-100, 101-120, andover 120 days. The highest current production was obtained when cows were openbetween 101 and 120 days (3476.1 kg milk). Correction coefficients were higher forshorter days open, starting with 1.14 when days open were between 20 and 40 days,and they were lower for days open length close to 101-120 days interval (1.01 for121-140 days open). Milk yield per normal lactation increased from 2960.4 kg whenprevious days dry was low (0-20 days dry) to the highest production of 3919.2 kg fordays dry interval between 61 and 80 days. The standardization coefficients for daysdry were higher for lower classes, starting with 1.32 in 0-20 days dry class anddecreasing down to 1.04 for the class of 81-100 days dry. Both for days open anddays dry, the milk yield was lower when these periods were shorter than in the casethese periods were longer, suggesting that milk production data should be adjustedat least for short periods of these reproduction indices.

Keywords


days open; days dry; milk yield; Romanian Spotted; primiparous cows

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LUCRARI STIINTIFICE ZOOTEHNIE SI BIOTEHNOLOGII (SCIENTIFIC PAPERS ANIMAL SCIENCE AND BIOTECHNOLOGIES)

ISSN print 1841 - 9364
ISSN online 2344 - 4576
ISSN-L  1841 - 9364
(former ISSN 1221-5287, E-ISSN 1841-9364)

PUBLISHER: AGROPRINT Timisoara, Romania
PAPER ACCESS: Full text articles available for free
FREQUENCY: Semiannual
PUBLICATION LANGUAGE: English
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Banat´s University of Agricultural Sciences and Veterinary Medicine "King Michael I of Romania" from Timisoara
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